Safety guard for power presses



BURKHARDT 2,289,901

SAFETY GUARD FOR POWER PRESSES Filed Jan. 6, 1941 INVENTOR. LOUIS BURKH'ARDTI 'BY 2 j K ATTORNEY.

Patented July 14, 1942 UNITED STATES PATENT OFFICE SAFETY GUARD FOR POWER PRESSES Application January 6, 1941, Serial No. 373,227

4 Claims.

This invention relates to new and useful improvements in safety guards for power presses and an object of the invention is to provide a simple and inexpensive guard consisting of but few parts which is operated by the normal press movements to sweep the operators hands or arms out of the path of movement of the descent of the tool.

Another important object of the invention is to provide a safety guard in the form of a pair of vertically disposed pusher arms which are disposed adjacent the center of the bed, and, which, upon descending movement of the ram, move outwardly in opposite directions so as to sweep either or both hands of the operator out of the path of movement of the tool.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the accompanying drawing forming a part of the description and wherein like numerals are employed to designate like parts throughout the several views,

Fig. 1 is a perspective view of the power press with the safety guard applied thereto,

Fig. 2 is a side elevational View of the safety guard detached from the press,

Figs. 3 and 4 are front elevational views of the safety guard at the two extremes of its movement.

Referring to the drawing in detail, the numeral ll] designates a power press having the usual vertically extending frame arms Ii in which is journaled a crank shaft [2 provided with a pulley wheel l3 adapted to be connected to a source of power to rotate the shaft 12. Connected to the crank portion of the shaft is a ram or tool l4 slidably mounted in vertical guides [5 for reciprocation with respect to a bed plate [5 to'operate upon the work disposed upon the latter. A foot pedal I1 operates the clutch mechanism on the shaft I2 in the usual manner to control rotation of the crank shaft and thus each stroke of the ram M.

For mounting the guard upon the press, a horizontal cross bar or other form of support is is bolted to the vertically extending arms ll of the press It]. Pivotally suspended as at [9 at their upper ends are a pair of vertical depending oscillatable arms which are each composed of a pair of sections 2| and 22 adjustably connected together with belt and slot connections 23 whereby the arms may be lengthened or shortened for any size press or to alter the extent to which the two arms reach outwardly in opposite directions as will be apparent as the description proceeds.

A pair of guard arms 24 and 25 are vertically adjustably mounted in fittings 26 secured to the lower ends of the arms 22 in vertical alignment with these arms and in spaced parallel relationship adjacent the middle of the forward edge of the bed of the press. A set screw 21 is associated with each fitting 26 so that after the guard arm has been adjusted with respect to its supporting arm 22, the set screw may be tightened to securely fix the guard arm with respect to its respective arm 22. The lower end of each arm 22 is provided with a pin or roller 28 extending rearwardly thereof to operate in a cam slot provided in a plate 30 secured to the ram of the press by means of the bolts 3|. A cam slot or way 29 is provided in the plate 30 for each guard arm 24 and 25, and as best shown in Figs. 3 and 4, these cam slots are inclined downwardly and inwardly in converging relationship to cause the arms 24 and 25 to move outwardly in opposite directions across the ram or tool as it begins to descend to cooperate with the die on the bed plate I5 and thereby sweep the operators arms clear of the descending tool. The upper ends of the slots 29 extend vertically and are substantially parallel to permit the ram or tool to complete its downstroke without further moving the guards 24 and 25 outwardly after they have reached their outermost positions as shown in Fig. 4. It will be obvious that the shape and angularity of the cam ways 29 can be varied to cause the arms 24 and 25 to move outwardly in opposite directions at any speed and at any stage in the descent of the ram which will insure the safest operation of the press. Also, by changing the length of the arms 2|] and the position of securement of the cam plate 30 to the press, the extent of oscillation of the arms 20 can be accurately controlled to adapt the attachment to any kind of press. Upon elevation of the ram or tool together with the cam plate 30, it will be seen that the guard arms 24 and 25 will be automatically moved inwardly to their normal positions shown in Figs. 1 and 3 by the rollers 28 entering the inclined portions of the slots 29 after the ram has been elevated to a certain extent, so that when the ram or tool is completely elevated and all danger to the operator is past, the guard arms will be disposed reasonably close together as shown in Fig. 3, thereby opening the throat of the press and permitting the operator to remove and insert work in perfect safety.

It will be understood from the foregoing description that very few parts are necessary to provide a very efiicient safety guard, and if desired a lazy tong structure can connect the guard arms 24 and 25 so as to protect the operator from inserting his hand under the ram in between the two arms during their separation or retraction.

It will also be understood that various changes in the size, shape and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A safety device for presses and the like comprising a pair of vertically disposed guard arms fulcrumed on the press at their upper ends and having their lower ends arranged adjacent the center of the forward edge of the bed of the press, a cam plate having a pair of downwardly and inwardly converging cam ways terminating in vertical substantially parallel ends, said cam plate being secured to the slide of the press, and cam guides carried by the guard arms and normally disposed in the lower converging ends of said cam ways when the ram is elevated, whereby when the ram descends, the guides ride outwardly in opposite directions causing the guard arms to move outwardly in opposite directions across the bed of the press as the ram moves closer to the bed.

' 2. A safety attachment for presses comprising a support adapted to be fixed to the frame of a press, a pair of guard arms pivotally suspended from their upper ends from said support to hang perpendicularly pendant from their pivots, a plate having a pair of inwardly converging ways adapted to be secured to the slide of the press, and said guard arms having cam guides adapted to operate in said ways.

3. A safety device for presses having a slide and a bed, a horizontal member adapted to be secured to the press, a pair of guard arms pivotally suspended from said member and each arm including a pair of sections, one of which is provided with a pair of bolts extending through a longitudinal slot in said other section, a plate secured to the slide of the press and having a pair of inwardly converging cam ways, and cam guides carried by said guard arms and operating in said ways upon reciprocation of said slide.

4. A safety device for presses and the like having a slide and a bed and comprising a pair of substantially parallel guard arms fulcrumed on the press at their upper ends to hang pendant therefrom, each of said arms including a pair of longitudinally adjustable sections, a plate secured to the slide of said press and having a pair of inwardly converging cam ways, cam guides carried by said guard arms and disposed in the lower converging ends of said ways when the slide is elevated and whereby when the slide descends the guides ride outwardly in opposite directions in said cam ways causing said guard arms to move outwardly in opposite directions across the bed of the press as the slide approaches said bed to sweep the operators arms clear of the bed.

LOUIS BURKHARDT. 

